Nitrogen-doped graphene-decorated LiVPO4F nanocomposite as high-voltage cathode material for rechargeable lithium-ion batteries

In this study, nitrogen-doped graphene decorated LiVPO4F cathode material is firstly synthesized via a facile method. Well-dispersed LiVPO4F nanoparticles are embedded in nitrogen-doped graphene nano sheets, forming an effective conducting network. The added nitrogen-doped graphene nanosheets greatly enhance the electronic conductivity and Li-ion diffusion of LiVPO4F sample. When tested as cathode material for rechargeable lithium-ion batteries, the hybrid electrode exhibits superior high-rate performance and long-term cycling stability between 3.0 and 4.5 V. It delivers a large discharge capacity of 152.7 rnAhg(-1) at 0.1 degrees C and shows a capacity retention of 97.8% after 60 cycles. Moreover, a reversible capacity of 90.1 mAhg(-1) is maintained even after 500 cycles at a high rate of 20 degrees C. The charge-transfer resistance of LiVPO4F electrode is also reduced in the nitrogen-doped graphene, revealing that its electrode-electrolyte complex reactions take place easily and thus improve the electrochemical performance. The above results provide a facile and effective strategy for the synthesis of LiVPO4F cathode material for high-performance lithium-ion batteries. (C) 2016 Elsevier B.V. All rights reserved.